1. Field of the Invention
The present invention relates to crystalline dihydrochloride of (6R,7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-((1S)-1-carboxyethoxyimino)acetam ido]-3-[(1-ethylpyridinium-4-yl)thiomethyl]ceph-3-em-4-carboxylate which is stable to heat and useful for pharmaceutical preparation and medical application, and a method for preparation thereof.
2. Prior Art
(6R,7R)-7-[(z)-2-(2-Aminothiazol-4-yl) 2-((1S)-1-carboxyethoxyimino)acetamido]-3-[(1-ethylpyridinium-4-yl)thiomet hyl]ceph-3-em-4-carboxylate is disclosed in Japanese Patent KOKAI No. 63-154622 as an amorphous sodium salt. This compound is an excellent compound having an antibacterial spectrum over a wide range including gram-positive bacteria to gram-negative bacteria.
As is described above, the amorphous sodium salt of the cephalosporin derivative described above is an extremely excellent compound which is non-toxic and has an antibacterial spectrum over a wide range. However, due to lack of thermal stability, this compound is not satisfactory for medical preparations and medical application.